Island Climate Update 22 - July 2002

Southern Oscillation Index (SOI) adopted from Bureau of Meteorology, Australia.
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Sub Surface Temperature along the Equator for May 2002 (adapted from TOA/TRITON).
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Sub Surface Temperature along the Equator for June 2002 (adapted from TOA/TRITON).
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El Niño Update
More progress towards the evolution of an El Niño in the last month
Probabilities have increased to 85% for an El Niño event affecting the whole of the Southwest Pacific by September this year.

Forecast validation
Forecast period: April to June 2002
Rainfall was projected to be above average in the Western and Eastern Kiribati and Vanuatu, and average to above average in New Caledonia, Fiji, Niue and Pitcairn Island. Average to below average rainfall was expected for much of the region from the Solomon Islands east to the Marquesas including the Northern Cooks, and central French Polynesia.
Average rainfall was forecast for other areas.
Rainfall was as expected for many of the forecast areas. However, it was higher than forecast in Samoa and the Marquesas and Austral Islands.

ENSO and Sea Surface Temperatures
Equatorial Pacific Ocean up to +1.5°C warmer than average
El Niño likely if conditions persist
In the tropical central Pacific, a band of anomalously warm water (+1.5°C above average) extends from Western Kiribati towards the coast of South America. An area of the Pacific which is also very much warmer than average lies southeast of Pitcairn Island (+2.0°C above average).
Generally, most of the Southwest Pacific is warmer than average ( +1.0 to 1.5°C).

An overview of the present climate in the tropical South Pacific Islands, with an outlook for the coming months, to assist in dissemination of climate information in the Pacific region.
Number 22 – 11 July 2002
June’s Climate: The South Pacific Convergence Zone (SPCZ) extended east from the Solomon Islands toward Tuvalu. However, it was virtually non-existent further east in the Southwest Pacific. A large area of enhanced convection with areas of above average rainfall affected the region from the Solomon Islands west to Papua-New Guinea.

Enhanced convection over Papua New Guinea and the Solomon Islands
Below average rainfall from Fiji to the Southern Cook Islands
In June, the SPCZ extended east from the Solomon Islands toward Tuvalu, being displaced north of its mean position in that region. However, it was virtually non- existent further east in the Southwest Pacific.
A large area of enhanced convection with areas of above average rainfall affected the region from the Solomon Islands west to Papua-New Guinea. In the north, the ITCZ was further south than usual, enhancing rainfall and cloudiness over parts of Kiribati.

Rainfall outlook for July to September 2002
Above average rainfall in equatorial latitudes from Nauru to Kiribati
Average to above average rainfall for the Solomon Islands, Vanuatu and Tuvalu
Average to below average rainfall in New Caledonia, Fiji, Samoa Tokelaus and Marquesas
Mainly around average rainfall in other areas
In the Western Pacific, the South Pacific Convergence Zone (SPCZ) extended east from Solomon Islands to Tuvalu and was virtually non-exsistent further east during June.

Sources of South Pacific rainfall data
This bulletin is a multi-national project with important collaboration from the following Pacific nations:
American Samoa
Australia
Cook Islands
Fiji
French Polynesia
Kiribati
New Caledonia
New Zealand
Niue
Papua New Guinea
Pitcairn Island
Samoa
Solomon Islands
Tokelau
Tonga
Tuvalu
Vanuatu
Requests for Pacific island climate data should be directed to the Meteorological Services concerned.
Acknowledgements
This bulletin is made possible with financial support from the New Zealand Agency for International Development (NZAID), Wellington, New Zealand, wi